Final answer:
The question is about hashing in the context of password security, specifically discussing the concept of iterative hashing and its impact on precomputation attacks and rainbow tables.
Step-by-step explanation:
The subject of this question is Computers and Technology. The question is discussing the concept of hashing in the context of password security. In this case, the question is referring to a method called iterative hashing, which involves running the value to be hashed through the hash function multiple times.
By increasing the computation time required for each password, iterative hashing makes it more difficult for attackers to use a technique called a precomputation attack. This type of attack involves creating a rainbow table, which is a large precomputed table of hashed passwords and their corresponding inputs. However, the effectiveness of a rainbow table is dramatically reduced when the hash function is applied iteratively, as the table would need to include exponentially more entries to cover all possible combinations.